Converter for transforming continuous electric current into isochronous undulatory currents



H. MAGUNNA.

CONVERTER FOR TRANSFORMING CONTINUOUS ELECTRIC CURRENT INTO ISOCHRONOUSUNDULATORY CURRENTS.

APPLTCATION FILED MAY 7. I9l3- RENEWED AUG. 1?. I920.

1,359,903. Patented Nov. 23, 1920.

1 769 '1 5 I 4 i 5% 1 T rm 1' H. MAGUNNA. CONVERTER FOR TRANSFORMINGCONTINUOUS ELECTRIC CURRENT INTO ISOCHRONOUS UNDULATORY CURRENTS.

APPLICATION FILED MAY 7. 191's. RENEWED AUG.

EET 2.

Patented NOV. 23, 1920. fiflj 4 SHEETS- 5 TA T/ON 7 3 W3 w w M ,4 i 7 6H H. MAGUNNA. v CONVERTER FOR TRANSFORMING CONTINUOUS ELECTRIC CURRENTINTO ISOCHRONOUS UNDULATORY CURRENTS.

APPLICATION FILED MAY 7, I9I3- RENEWED AUG. .2 I920.

.1 ,359,903. Patented Nov. 23, 19209 4 SHEETS-SHEET 3.

l/VVE'NTOR H. MAGUNNA.

CONVERTER FOR TRANSFORMING CONTINUOUS ELECTRIC CURRENT INTO ISOCHRONOUSUNDULATORY CURRENTS.

APPLICATION FILED MAY 7, I9I3- RENEWED AUG.I2.1920.

1,359,903. Patented NOV. 23, 1920 SHEETS-SHEET 4.

UNITED STATES P A lIENT OFFICE.

51mm MAGUNNA, 0F PARIS, FRANCE, AssIeNon T0 SOCIETE DES TELEGRAPHESMULTIPLEX (SYSTEME E. MERCADIER-H. MAGUNNA), 0F PARIS, FRANCE.

CONVERTER FOR TRANSFORMING CONTINUOUS ELECTRIC CURRENT INTO ISOCHRO-NOUS UNDULATORY CURRENTS.

Application filed Kay 7, 1913, Serial No. 766,129. Renewed August 12,1920. Serial No. 403,149.

To all whom it may concern:

Be it known that I, HENRI MAGUNNA, a citizen of the Republic of France,and residing in Paris, France, have invented certain new and usefulImprovements in Converters for Transforming Continuous Electric Currentinto lsochronous Undulatory Currents, of which the following is aspecification.

In the known converters for transforming continuous electric currentinto isochronous undulatory currents, the movements of the tuning forksor other vibrating bodies have been maintained electrically. They can bedivided into two types, namely, (1) converters in which the maintenanceof the motion and the transformation of the current are simultaneous,such as those of Varle Paul Lacour, Elisha Gray, Mercadier,Klercadier-Magunna;

(2) Converters in which the maintenance of the motion and thetransformation of the current are distinct, such as those of PaulLacour, Mercadier, Van Ryselberghe.

The irregular action which is obtained by means of two styles or twotuning forks or with microphones (which give weak undulatory currents of"cry little power) has caused the latter of these two types to be givenup. I 4

Among the converters in which the transformation of the current andmaintenance of the oscillation are simultaneous, the electric tuningfork of i\'Iercadier-i\ Iagunna has given satsfactory results; itcomprises an electric circuit for maintaining the vibrations and a coilin this circuit connected in parallel to the primary of an inductiontransformer, which traversed'by a con tinuous undulatory current. Thissystem has a disadvantage, which is due to the principle on which itdepends: the production of the undulatory current is a function of thestrength of the current, which trav erses the vibrator, and of thepressure of the style on the fixed contact. The action is consequentlylimited more particularly as regards the regulation of the currentstrength. since the electric tuning fork plays the double part of motorand transformer.

Also, the machines. which have been proposed for producing undulatorycurrents,

and which depend upon the speed of. the driving motors, cannot complywith the requirement of constant periodicity. In fact, with motors, evenwhen provided with mechanical or electric regulators, constancy PatentedNov. 23, 1920.-

of speed cannot be maintained -within- 1/200th of a second, a figurewhich is absolutely indispensable for mechanical syntony. The statementthat an apparatus has a speed constancy within 1/200th of a secondmeans, for instance, that-a tuning-fork having a normal frequency of 800per second, can have a maximum variation of speed,

more or less, by l/QOOth, that is to say, that 7 its frequency willalways be embraced between 796 and 804; double vibrations per second.The maximumof variation of speed, in the case given, is 8 doublevibrations. In the case of a tuning-fork having a normal frequency of400, the maximum of variation of speed would be 4 double vibrations.

It has been found in practice that an electric tuning fork, which hasbeen working for 12 hours, had an average constancy within 1/200th of asecond, hence the satisfactory results obtained by this apparatus. F orthis reason it has been considered ad,- visable to keep to the method ofgenerating isochronous undulatory currents by vibrat ing rods, but tomaintain perfectly separate the means for sustaining the vibrations andfor the transformation of the continuous into undulatory current; andthis has led to a mechanical. method of maintaining the vibrations ofthe rods; which is the object of the present invention. Under theexpression vibrating rods, are included tuning forks or any othervibrating bodies of which the vibrations follow the pendulum law, thatis to say are sinusoidal. H V

A rod or tuning fork is kept in continual vibration by placing the freeend of one of its prongs in contiu-twvitli a body covered with rosin.this body being displaced constantly and regularly in contact with theedge of the fork. This method can be carried out in three differentways, which are only modified constructions of the same generalprinciple, vi7,., by endless bands, by cylindrical drums. and by flatdisks.

The accompanying figures illustrate difmaintaining the vibrators I ofthe constructions of the contact il'illlqfls' and of the circuits inwhich the vibrators, serving to convert the continuous into isochronousundula-tory currentsfare placed.

"In said drawings;-

Figure 1 illustrates in side elevation, somewhat diagrammatically, andpartly in section, a converter according to the pres ent invention (theelectric circuits being omitted} Fjof'Q is a plan view of the deviceshown in Fig. 1. the parts being omitted.

Fig. 3 is a side elevation of a spindle and pulleys which may be used inplace of the spindle and pulley shown in Fig. 1.

Fig. i illustrates the parts in somewhat the same manneras Fig. 2. aplurality of tuning-forks being shown.

Fig. 5 's a plan view similar to Fig. 2, of certain of the parts, andshowing a tension roller 15.

Fig. 6 is a. vertical sectional view of a rubbing cylinder.

Fig. 7 is a plan view thereof in conjunction with a. tuning fork.

Fig. 8 is a vertical sectional view oi a flat rubbing disk inconjunction with a tuningfork.

Fig. 9 is a side elevation of said parts.

10 is a plan view of the disk shown in Fig. 8.

Fig: 11 is a plan view, with parts in section. of a tuning-fork withcertain parts in conjunction therewith used for the present invention.

Fig. 12- is a side elevation. with parts in section, of the parts shownin Fig. 11.

Fig. 13 illustrates in side elevation an apparatus for sustaining thevibrations.

Fig. 14; is a transverse section on the line XIXXIX Fig. 15.

15 is a plan view of the parts shown in Figs. 13 and 14:.

Fig. 16 illustrates a detail of the contacts upon the tuning-fork.

Fig. 17 illustrates a detail of the circuit terminal which is located onthe base.

Fig. 18 illustrates a contact piece in detail.

Figs. 19 and 20 illustrate tuning-forks and contact pieces inconjunction therewith.

Fig. 21 is a detail view of the contact piece 32 shown in Fig. 19.

Fig. 22 is a plan view of said contact iece.

Figs. 2-3 and 2% illustrate in end view and side elevation.respectively, a tuning fork, and an interrupter actuated thereby.

Figs. 25, 26 and :27 illustrate an electrical system wherein theinvention is applied to wireless telegraphy or the like.

In Figs. 1 and 2, two vertical spindles 2 and 3, are shown. supported ina frame 1 and on these spindles are mounted two grooved pulleys 4. and5; an endless band 6 runs in the grooves of these pulleys and thespindle 3 is driven b a mechanical method, which will be describedlater. The arrow f (Fig. '2) shows the direction of rotation of theband. A stick of rosin 7 rubs constantly against the band 6; a tuningfork 9 is rigidly secured to a support 8 and touches the band at 10.

As soon as the band is in motion, the tuning fork vibrates. The tuningfork carries 'on its prongs two movable masses 11 and 12 for adjustingthe pitch. The bands used are of leather (cow or calf hide), scraped andpumiced and the skived ends are joined together by a rubber solution.Other suitable materials bcsidcs leather can be used. The tuning fork isrubbed by the belt on one of its edges 13. Several forks placed side byside can be actuated by a single band, as shown in Fig. 4, if stretchingrollers 14 are placed between them. one after each pair of forks.

The speed and tension of the band are both adjustable. To adjust thetension, the spindle 3 can be displaced by turning the screws 3. Fig. 1.Also by means of a roller 15 Fig. 5 the tension can be adjusted duringthe action of the apparatus. The socket 8 in which the stem of thetuning-fork is fixed (Fig. 2) is grooved so that the angle 3 ofengagement between the prong and the band. and the pressure of thecontact between them can be adjusted. It is found by experience that thesame speed of engagement between the band and the fork acts perfectlythrough the range of an octave. The contact pressure should increasewith forks of higher pitch. which is to be expected, as the forks ofhigher pitch are shorter and hence stifi'er. hen the range is greaterthan an octave or when forks of very high or very low pitch are usedseveral belts can be arranged in parallel, running on pulleys ofdifferent diameter on the same spindle, and consequently havingdifferentlinear velocities, as indicated by the spindles 2' 3 andpulleys 5 5 5 Fig. 3. This arrangement permits of producing in differentcircuits currents of different frequencies, where the frequencies aremore than an octave apart.

Sustaining fire vibration by cg Zindfical drums.

A leather cylinder 18 is fixed on a drum 16 (Figs. 6 and '7). which ishollowed out at the center and mounted on a spindle 17: the

periphery of the drum engages one of the "ends of the fork 9, in thesame way as the 106 over which the band 107 passes.

able tension on the drum 19 (Figs. 8, 9, 10), which is mounted on adriving spindle 21;

Mechanical system of mounting the vibratz'ng forks.

The tuning forks 9 (Fi 11 and 12) are of the type with aperio 10contacts. The contact between the movable member 32 and the fixed member33 provided with a platinum tipped screw is always in a lane which isgeometrically determined. he stem of the fork is insulated from the baseand is adapted to form part of an electric connection, the otherconnection being the fixed terminal 33 carrying the interrupting screw.The whole is mounted on supports 35, which are bad conductors of sound(cork, caoutchouc).

The action of the vibrator is as follows As soon as the rosined band isstarted, it sets in vibration the fork or forks which are in contactwith it, and it is only necessary to adjust the position of theinterrupting screw with respect to the platinized contact of the fork;the mechanical contact is established as soon as a pure notecorresponding to that of the fork is heard.

Figs. 13, 14 and 15, represent in more complete detail, a converteraccording to the present invention.

On the base plate 99 is mounted, in,overhung bearings on the pedestal100, a small electric motor 101 with vertical spindle, which drives, bymeans of a pulley 102 keyed to the lower part of its spindle and a band103, another pulley 104 mounted on a vertical spindle 105, to which issecured a pull gay 1s band is in contact with the tuning forks, and alsopasses over another pulley 108, mounted on a vertical spindle 109. Astretching roller 110 is placed behind the band and rests on it, so asto adjust the tension; the axle of the roller is mounted on an eccentricwhich moves it to or from the band.

()n the opposite side to the pulleys and the motor two tuning forks 111,11.2, of different length, are mounted and carried on slides 113, 114,which can move in suitable guides formed in the base plate. These slidescan be fixed in the positlons suited to insure the desired contactbetween the forks 111 and 1 12 and the band 107. The forks are mountedon vertical axes '115 and 116, which allow the angle of engagementbetween the forks and the band to be varied. Each of the forks carriesalso at the end of the stem :1 terminal 117, 118 for connecting upcurrents and also current terminals 119, 120.

The strength of the undulatory.current' rating the interrupting screwaxially, as

shown in Fig. 18, so as to be able to inject a current of air from ablower coupled to the junction 136.

Fig. 16 is a part view of the side of a tuning fork showing threecontacts 131. These contacts are preferably mounted on small metallicstrips 132 fastened by two screws 133 to one prong of atuning fork andare so proportioned that they have no natural period of their own andare held between metal washers, of aluminium for example.

The interrupting screws 121, 122 can be adjusted, and fixed in positionso as to regulate their distance from the strip carried by the forks, bymeans of a special mountlng shown in vertical section in Fig. 17. Thisarrangement consists of a pillar 123 provided with two screwed holes124, 125 and a vertical hole in which a cylindrical piece 127 can befrictionally displaced. This cylindrical piece has an aperture of thesame diameter and screwed to the same pitch as the holes 124, 125 and isprovided with a screwed stem 129, with which engages a milled headed nut130, resting on the annular end of the pillar 123. When the cylindrical)iece 127 is pulled upward by the nut 130, t e screw 121 is tightenedmore or less and may be completely jammed without the need of any locknut.

The terminal for leading the current in the mechanically sustainedtuning forks can, instead of being mounted on the side of one of theprongs, consist, as shown in Fig. 19, of a copper bush 151 which isplaced inside-a second insulating bush 152 in a corresponding apertureformed in the fork, and is internally screw-threaded so as to permit ofthe adjustment of the regulating screw 153, which can be held in position by the lock nut 154. This screw is displaced, during the vibrationsof the fork, relatively to the contact strip 32, which is secured to theother prong and is balanced by the counterweight 155.

This arrangement allows a double amplitude of vibration to be obtainedfor the same frequency, since the two prongs act together and approachor recede through distances twice as great, as when the break iseffected on the side of one prong only of the fork.

In the modification shown in Fig. 20, contact strips 32 are placed oneach side of one prong of a tuning fork and each is displaced relativelyto a fixed terminal with a regulating screw like that shown in Fig. 19.By: this arrangementa frequency twice that of the vibrating fork isobtained. A counter weight 155 is arranged as before to balauce theweight of the contact strips 32 and their fastening screws.

The construction of the contact strips is shown in Figs. .21 and 22. Thesteel strip 32 is associated with a thin strip of copper 179 to increasethe conductivity of the circuit between the contact and the screws,which secure the strip to the prong of the fork This arrangementprevents the strip from being broken by the annealing due to the heatingby the current traversing it, and allows the use of a thin elasticstrip. The strip is aperiodic. that is, its vibrations are damped oropposed, partly owing tothc non-corresponding relation between its nodesandthe distance apart of its supports and partly to the manner in whichit is placed between comparatively plastic materials, such as thealuminium washers 180 and 181.

Between the contact strip and the end 182 c'ei'he contact 183 a thincopper washer 184 is placed. The elasticity of the composite strip maybe regulated by increasing or minishing the thickness of the steelstrip. It is obvious that the strip of copper may be placed aboveinstead of beneath the steel strip.

For certain purposes the amplitude of the oscillations of the prong orother vibrator can be augmented and the contact point removedsufficiently far from the prong to enable the break to take place in aninsulating medium, such as petrol, and in this way to protect thecontacts from disintegration.

For this purpose a lever 13? as shown in Figs. 23 and 2fis arranged tooscillate about a point 138 in a plane at right angles to the plane ofthe prong of the tuning fork. and is held against the prong by a spring139.

The upper bent. end of the lever 13? rests against the vibrating surface140. and consequently undergoes oscillations in synchronism with thissurface. The lower end carries an interrupting screw 142 immersed in avessel 1&1 filled with petrol.

in this method also the frequency can be doubled by placing anotherscrew lei-3 opposite the screw 142 or even quadrupled by placing a thirdscrew H4 in an extension of the mean position of the oscillating lever137.

Electric oscillations especz'aZZy for the purpo e of wireless relaympAye-This system of converting continuous current into isoclnfonousundulatory currents can be utilized not only in ordinary line telegraphybut also in any other applications, which re quire an isochronousinterrupter. for example iu the generation of electric oscillations.more especially for wireless telegraphy.

To transform continuous current into electric oscillations for thepurpose of wireless telegraphy two methods can be employed.

(1) Direct excitation as shown in Fig.

The primary 6? of an induction coil 68 or of a t'ansformer with closedmagnetic circuit is connected by a key 69 to the con tact of the fork 70and to a source of continuous current 71. A condenser 72 absorbs thespark. When the tuning fork 70 is maintained in vibration by the band 73it is only necessary to close the key (39 for singing sparks to traversethe air gap 74, which is connected on one side to earth 75 and on theother side to the antenna 76. The frequency of the trains ofoscillations corresponds to the number of complete oscillations of thefork.

(2) Excitation by induction (Fig. 26).

In the circuit of the secondary 77 of the induction coil 68 or of atransformer with closed magnetic circuit, there is a spark gap 81,across which is placed a condenser 82 and primary coil 7 8; thesecondary coil 79 is placed between earth and the antenna 80.

In these different arrangements the trains of oscillations may have anydesired frequency by providing tuning forks of the required frequencies;in the case of four forks the arrangement would be the following In thecircuit of the primary 8d: of the induction coil Fig. 27) are inserted 4derived circuits, each comprising keys 8588 and tuning forks acting asvibrators 89-92, which all have one edge acted on by the same band and acondenser 93 is placed in shunt between the battery and the derivedcircuits.

In the case of wireless stations of small energy giving out sustainedoscillations, tickers can be used for the transmission ofelectromagnetic waves.

1 claiml. A device for changing a continuous current of electricity intoan isochronous undulatory current, comprising an electric circuit, anisochronous vibrator acting as an interrupter in said circuit, and meansfor vibrating said vibrator, said means comprising an endless beltadapted to rub against said vibrator.

2. A device for changing a continuous current of electricity into anisochronous undulatory current, comprising an electric circuit,atuning-fork acting as an inter rupter in said circuit, and means forvibrating said fork, said means comprising an endless belt adapted torub against said fork.

3. A device for changing a continuous current of electricity into anisoehronous undulatory current, comprising an electric circuit, anisochronous vibrator acting as an interrupter in said circuit, andfriction means with a continuous movement for maintaining in vibrationsaid vibrator. said vibrator having a plurality of contacts. and saidcircuithaving a plurality of corresponding contacts.

at. A device for changing a continuous current of electricity into anisochronous undulatory current, comprising an electric circuit,anisochronous vibrator actin as an interrupter in said circuit, andriction means with a continuous movement for maintaining in vibrationsaid vibrator, said vibrator having a contact with an axial air passa etherein.

5. 5 device for changing a continuous current of electricity into anisochronous' undulatory current, comprising an electric circuit, anlsochronous vibrator actin as an interrupter in said clrcuit, andfi'iction means for vibrating said vibrator, said vibrator having acontact thereon and said contact compnsing stri s of metal havingunequal vibration perio s.

6. A device for changing a continuous current of electricity into anisochronous undulatory current, comprising an electric scribingwitnesses.

HENRI MAGUNNA. WVitnesses:

GABRIEL BELLIARD, Locum MEMMINGER.

